Minimize bootstrap footprint

[stigok]

Less size, but also gets rid of Tether nagging about missing dependency

bootstrap.min.js:7 Uncaught Error: Bootstrap tooltips require Tether (http://tether.io/)
    at bootstrap.min.js:7
    at bootstrap.min.js:7
    at bootstrap.min.js:7

[stigok]

Also remove unused CSS bootstrap features

[stigok]

For the SASS code, simply commenting out unused things in _sass/haus/_custom-bootstrap.scss is enough.